Phil Mickelson is one of the greatest golfers in history, but he’s not exactly bringing in younger TV viewers. (Getty Images)

Sports Business Journal has released a remarkable new study documenting the average age of TV sports viewers, and the news isn’t good for several sports. Golf and NASCAR in particular, two sports already struggling to retain viewers, are appealing largely to a much older base … a trajectory that doesn’t bode well for the future.

Magna Global conducted the study for SBJ, investigating live, regular-season coverage of sports on both cable and broadcast TV for three years: 2000, 2006, and 2016. The median age of viewers in most sports is aging faster than the U.S. population as a whole, though — a sliver of good news — not faster than the median age of prime-time television viewers.

Here’s a breakdown of the aging process, across top sports, including average age of viewer and change in that average age since 2006:

Overall, the oldest viewership belongs to the PGA Tour’s over-50 Champions Tour, the PGA Tour itself, and figure skating, all of which had an average viewer age of 64 in 2016. Right behind, at age 63, were the LPGA and horse racing. On the other end of the spectrum, several soccer leagues boasted viewers averaging 39 to 40 years, with the NBA right there at age 42.

The greatest average age change since 2000 is a bit of a surprise: pro wrestling, which has seen its average age increase more than a quarter-century, 26 years, over the last 16 years. That would seem to suggest that the sport has significantly turned off former fans while not bringing in anywhere close to an equivalent number of replacements. By contrast, women’s tennis has seen its average age drop by three years (presumably, the Serena Williams effect) since 2000, while the NBA has remained virtually consistent at an age increase of only two years.

Why is virtually every sport up in average age of television viewers? Simple: technological advances. Viewers simply don’t feel the need to watch on television what they can catch on their phones in highlight form. (The study notably did not track online viewing habits, which would skew results for 2016 in particular.) Virtually every sport is working to make its digital presence more intriguing to younger viewers, spreading content and highlights across multiple platforms.

While these results aren’t particularly shocking — golf drawing an older crowd than the NBA isn’t exactly a revelation — they illustrate a need for certain sports to find a way to remain relevant by drawing in younger viewers. Golf, for instance, has seen Tiger Woods leave the stage, while NASCAR has seen the exit or impending exit of stars Jeff Gordon, Tony Stewart, and Dale Earnhardt Jr., all four of whom were popular with once-younger viewers. Jordan Spieth, Dustin Johnson, Chase Elliott, Austin Dillon … if you don’t know who these guys are, that’s part of the problem these sports face, now and in the immediate future.